org.apache.sshd.common.PropertyResolver Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.sshd.common;
import java.nio.charset.Charset;
import java.util.Collections;
import java.util.Map;
import org.apache.sshd.common.util.MapEntryUtils;
/**
* Indicates an entity that can be configured using properties. The properties are simple name-value pairs where the
* actual value type depends on the property. Some automatic conversions may be available - e.g., from a string to a
* numeric or {@code boolean} value, or from {@code int} to {@code long}, etc.. Note: implementations may decide
* to use case insensitive property names, therefore it is highly discouraged to use names that
* differ from each other only in case sensitivity. Also, implementations may choose to trim whitespaces, thus such are
* also highly discouraged.
*
* @author Apache MINA SSHD Project
*/
public interface PropertyResolver {
/**
* An "empty" resolver with no properties and no parent
*/
PropertyResolver EMPTY = new PropertyResolver() {
@Override
public PropertyResolver getParentPropertyResolver() {
return null;
}
@Override
public Map getProperties() {
return Collections.emptyMap();
}
@Override
public boolean isEmpty() {
return true;
}
@Override
public String toString() {
return "EMPTY";
}
};
/**
* @return The parent resolver that can be used to query for missing properties - {@code null} if no parent
*/
PropertyResolver getParentPropertyResolver();
/**
*
* A map of properties that can be used to configure the SSH server or client. This map will never be changed by
* either the server or client and is not supposed to be changed at runtime (changes are not bound to have any
* effect on a running client or server), though it may affect the creation of sessions later as these values are
* usually not cached.
*
*
*
* Note: the type of the mapped property should match the expected configuration value type -
* {@code Long, Integer, Boolean,
* String}, etc.... If it doesn't, the {@code toString()} result of the mapped value is used to convert it to the
* required type. E.g., if the mapped value is the string "1234" and the expected value is a
* {@code long} then it will be parsed into one. Also, if the mapped value is an {@code Integer} but a {@code long}
* is expected, then it will be converted into one.
*
*
* @return a valid Map containing configuration values, never {@code null}. Note: may be
* immutable.
*/
Map getProperties();
default boolean isEmpty() {
return MapEntryUtils.isEmpty(getProperties());
}
default long getLongProperty(String name, long def) {
return PropertyResolverUtils.getLongProperty(this, name, def);
}
default Long getLong(String name) {
return PropertyResolverUtils.getLong(this, name);
}
default int getIntProperty(String name, int def) {
return PropertyResolverUtils.getIntProperty(this, name, def);
}
default Integer getInteger(String name) {
return PropertyResolverUtils.getInteger(this, name);
}
default boolean getBooleanProperty(String name, boolean def) {
return PropertyResolverUtils.getBooleanProperty(this, name, def);
}
default Boolean getBoolean(String name) {
return PropertyResolverUtils.getBoolean(this, name);
}
default String getStringProperty(String name, String def) {
return PropertyResolverUtils.getStringProperty(this, name, def);
}
default String getString(String name) {
return PropertyResolverUtils.getString(this, name);
}
default Object getObject(String name) {
return PropertyResolverUtils.getObject(this, name);
}
default Charset getCharset(String name, Charset defaultValue) {
Object value = getObject(name);
return (value == null) ? defaultValue : PropertyResolverUtils.toCharset(value);
}
static boolean isEmpty(PropertyResolver resolver) {
return (resolver == null) || resolver.isEmpty();
}
}